"Guest Expert" by Allen K. Lang is a science fiction short story written in the early 1950s. The narrative explores the dark moral dilemmas surrounding overpopulation and the drastic measures proposed to resolve it through the perspective of a Martian visitor. The story examines themes of survival, ethics, and the consequences of human choices. In this chilling tale, Earth faces severe issues due to overpopulation, prompting a Martian visitor to propose a radical solution: culling the human population by half. The protagonist, a Secretary, grapples with the moral implications of this proposal while hearing the Martian's justification based on historical suffering caused by famine, war, and disease. After a vote among his colleagues, the Secretary ultimately consents, leading to a horrifying conclusion where each woman and girl on the planet inexplicably dies, leaving behind a stark reality that starkly contrasts the Martian's promise of survival through sacrifice, effectively addressing the immediate population crisis at an unfathomable cost. (This is an automatically generated summary.)